Fixing pulley wheels to plate-like structures

ABSTRACT

A stud (1) for mounting a pulley (2) to a plate (3) by a cold forming process has a large diameter head (5), a cylindrical shank (6) which acts as the stub shaft for the pulley (2), the end of the shank remote from the head being connected to a smaller diameter shank (7) via a shoulder (9) (which may include an annual grove (10) into which the plate (3) is deformed), and, beyond the smaller diameter shank, an e.g. threaded shaft (8). To resist rotation after the stud (1) is cold formed to the plate (3), the stud (1) has ribs or studs or flat facets on the shoulder or on the narrow shank (7) against which the plate is cold formed.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to fixing pulley wheels to plate-like structures.

There are numerous applications of pulley wheels in a wide variety ofmechanical constructions. Very often the pulley wheel is to be attachedto a metal sheet and it is well-known to do that by attaching a stubshaft or axle to the sheet, e.g. by spot welding and then fixing apulley wheel thereon, the pulley wheel being retained, e.g. by a springclip engaging in a peripheral groove in the stub shaft, conventionallywith the interposition of a washer or bush. In many cases, the metalsheet then is has to be fixed in place in the device in question, forwhich purpose further and separate fixing means are provided. Thus theinstallation of a pulley wheel in a piece of equipment requires twosorts of fixing process, which is clearly consumptive of machinery, timeand manual (or robotic) manipulation.

We have now found that by careful design it is possible to produce apulley wheel arrangement, where the fixture of the stub shaft for thewheel itself and the provision of fixing means for the assembly of stubshaft on a plate-like metal substrate are combined.

GB 318 182A describes improvements in and relating to securing parts andarticles to metal and other plates, sheets and the like by riveting. Itdiscloses, in FIGS. 8 and 9 attaching a bolt with an annular shoulder toa metal plate. DE 41 31 098A discloses, in FIG. 2, a pulley mounted on abolt.

According to a first feature of the present invention, there is provideda stud having a cylindrical shank of a first diameter connected to ashank portion of a second, smaller diameter via a shoulder having anannular groove, the shank portion mounting a shaft provided with afixing configuration;

characterised in that

the shank is adapted to act as a stub shaft for a pulley and is providedwith a head of enlarged diameter relative to the shank to retain thepulley; the end of the shank remote from the head being connected to thesmaller shank portion; the annular groove extending from the plane ofthe shoulder towards the head; and the shaft extending away from thehead.

Such a stub may be used, as set out in claim 6, to mount a pulley to ametal plate by providing in the metal plate a hole of diameter equal toor slightly exceeding that of the smaller shank portion;

placing the pulley over the first diameter shank portion, the axialdimension of the pulley being at most equal to the axial extent of thefirst diameter shank portion;

inserting the smaller shank portion through the hole in the metal plate,and;

cold forming the smaller diameter shank portion to expand it and fit itsecurely into the metal plate.

This leaves a stud attached to the metal plate with the pulley wheelmounted to one side of the plate and the shaft extending on the otherside. The shaft may be fixed in place where desired simply by insertingit through a suitable hole in the structure of the machine or the likeand attaching a mating fixture, for example a nut, optionally with alocking washer, if the nut is not itself self-locking, onto the shaft ifit is threaded.

According to a second feature of the invention, there is provided anassembly of a stud, pulley and metal plate, wherein the stud has a headof large diameter relative to a shank extending from the head, the shankbeing cylindrical and having a first portion constituting a stub shaftfor the pulley, and wherein the end of the shank first portion remotefrom the head is connected to a smaller diameter shank portion via ashoulder, and wherein located on the side of the smaller diameter shankportion and extending away from the head is a shaft having a fixingconfiguration, there being on one of the shoulder or the smallerdiameter shank portion a torsional resistance-enhancing configuration,and wherein the metal plate has an aperture, the edges of which are atleast partly deformed into contact with the torsionalresistance-enhancing configuration, and the pulley being held captivebetween the plate and the head of the stud.

Preferably the exterior surface of the smaller diameter shank portionand/or the interior of the annular groove and/or of the shoulder ifwithout a groove is/are provided with a torsional resistance-enhancingconfiguration; this may be, for example, axial ribs or radial ribs orstuds or flat facets around which the metal of the plate deforms duringcold-forming. Such formations render the stub shaft resistant torotation about its axis once it is mounted to the plate, by providing asecure physical interlocking between the formations and the parts of theplate deformed against them.

If the axial dimension of the pulley wheel is less than that of thelarger diameter portion of the shank, one or more spacers or washers maybe provided as appropriate to prevent the pulley moving axially on theshank after the stud has been installed in the metal plate.

The present invention is of particular value in connection with theconstruction of automobile window movement systems, where movement ofthe window, e.g. up or down in a driver or passenger door, isconventionally achieved by mounting the window in generally verticallyextending tracks and providing, on the bottom of the window, some formof mechanical linkage which raises or lowers the window itself. Thedrive for that mechanical linkage is conventionally provided either by arotatably mounted crank handle set on the inside of a door or it may beproduced from an electric motor. In either case, the conventional drivetransmission method used is that of an extending belt or wire which runsover a series of pulleys. Mounting the pulleys to the usually metalplate components of the mechanism can save substantial quantities oftime in the overall assembly of the window and winder gear.

The invention is illustrated and further explained, by way of example,with reference to a variety of studs adapted for use in window windinggear applications and which are shown in the accompanying drawings, inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a stud, pulley and plate assembly,

FIG. 2 is a cross section through the assembly in assembled form,

FIGS. 3, 4 and 5 show alternative versions of the stud shown in FIG. 1,

FIGS. 6 to 11 show versions of the stud without an annular groove, and

FIGS. 12 to 14 show studs corresponding to those shown in FIGS. 9 to 11respectively, but including a groove.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1 and 2 of the drawings, FIG. 1 shows a stud 1,pulley wheel 2 and plate 3 prior to assembly. As can be seen, stud 1consists of a head 5, shank portion 6 fitting the inner aperture in thecentre of pulley 2, narrower shank portion 7 and threaded shaft 8. Shankportion 7 is surrounded by a groove 10 in the flat shoulder 9 at the endof shank portion 6, and has six equiangularly spaced external ribs 11,which have tapered ends and which do not extend all of the way alongshank portion 7.

Shank portion 7 (or at least the top portion thereof as shown in thedrawing) fits a hole 20 in plate 3, which may be thought of as acomponent of a window lifting assembly.

In order to f it these components together, they are assembled as shown,optionally with the interposition of a pair of spacing washers 22 (shownin dashed lines in FIG. 1), with the shank portion 7 inserted into hole20. Using a suitable cold-forming tool, the plate 20 is first pusheddown on shank portion 7 until it abuts the shoulder 9, and then theupper portion of shank portion 7 is deformed, pushing the edges of thehole 20 into the groove 10, and with the final shape being as indicatedin FIG. 2. The stud 1 is now firmly fitted into plate 3, and cannotrotate as the ribs 11 lock into the deformed metal of that sheet. Thefastening method is analogous to that described in U.S. Pat. No.3,938,239 and U.S. Pat. No. 4,018,257, and can be carried out usingappropriate press tools in known fashion. More than one stud and pulleyassembly may be fitted to the same sheet metal component if appropriate.

The assembly of sheet metal component and pulley(s) may easily bemounted in place, e.g. on suitably apertured flanges in a vehicle doorshell, by passing the threaded shafts 8 through the apertures in thedoor shell and securing the assembly in place by threading a locknut ornut and locking washer on to the shaft 8 and tightening the nut to thedesired torque.

FIGS. 3, 4 and 5 show variations of stud 1, each having an annulargroove 10, a head 5, shank portion 6, narrower shank portion 7 andthreaded shaft 8. Instead of the ribs 11 on the shank portion 7 as shownin FIG. 1, the embodiment of FIG. 3 is provided with six equi-angularlyspaced struts 30 at the junction of the narrower shank portion 7 and thegroove 10. In FIG. 4 there are four radially-extending ribs 32 on thesurface of the groove 10, and in FIG. 5, the outer edge of the groove isprovided with a castellated raised part 34. The features 30, 32, 34 allprevent relative rotation of the stud 1 once it is mounted to a plate.

Other forms of stud, denoted 1A, are shown in FIGS. 6 to 11. Each stud1A has a head 5, shank portion 6, narrower shank portion 7 and threadedshaft 8, as for stud 1 in FIGS. 1 to 5.

In FIG. 6, the torsional resistance-enhancing means comprise a number ofaxially-extending studs 36 on the shoulder of the shank portion 6adjacent the narrower shank portion 7; in FIG. 7, the surface of theshoulder is in triangular toothed form 38, and in FIG. 8 the shoulder isradially fluted, 40.

In FIG. 9, the outer surface of the narrower shank portion 7 is providedwith a large number of small plane facets 42. In FIG. 10 the narrowershank portion 7 is hexagonal in cross-section with six large facets 44,and in FIG. 11 the narrower shank portion 7 is square in cross-sectionwith four large facets 46.

FIGS. 12 to 14 show studs as in FIGS. 9 to 11 respectively, but where ineach case instead of a plane shoulder between shank portion 7 andthreaded part 8 there is a shoulder with a groove 10 in it, into whichgroove the edges of the plate 3 are deformed when the assembly of plate,pulley and stud is made.

Although the invention has been described with particular reference toits use in the construction of window actuation assemblies in theautomotive industry, it will be appreciated that there are numerousother areas of application of pulleys, in many of which the combinedpulley fixing and component fixing approach identified above may beusefully employed.

What is claimed is:
 1. An assembly for a stud (1), pulley (2) and metalplate (3), the stud having a head (5) of enlarged diameter relative to ashank extending from the head, the pulley being held captive between theplate and the head of the stud, the shank being cylindrical and having afirst portion (6) constituting a stub shaft for the pulley; and whereinthe end of the shank first portion remote from the head is connected toa smaller diameter shank portion (7) via a shoulder (9), and whereinlocated on the end of the smaller diameter shank portion and extendingaway from the head is a shaft (8) having a fixing configuration, therebeing on one of the shoulder and the smaller diameter shank portion atorsional resistance-enhancing configuration (11), and wherein the metalplate has an aperture, the edges of which are at least partly deformedinto contact with the torsional resistance-enhancing configuration. 2.An assembly according to claim 1 wherein located to either side of thepulley are one or more spacing washers (22).
 3. An assembly according toclaim 1 wherein the fixing configuration is an external screw thread. 4.A method of mounting a pulley on a metal plate using a stud having acylindrical shank of a first diameter connected to a shank portion of asecond, smaller diameter via a shoulder having an annular groove, theshank portion mounting a shaft provided with a fixing configuration; theshank being adapted to act as a stub shaft for a pulley and beingprovided with a head of enlarged diameter relative to the shank toretain the pulley; the end of the shank remote from the head beingconnected to the smaller shank portion; the annular groove extendingfrom the plane of the shoulder towards the head; and the shaft extendingaway from the head; the method comprising: providing in the metal platea hole of diameter equal to or slightly exceeding that of the smallershank portion; placing the pulley over the first diameter shank portion,the axial dimension of the pulley being at most equal to the axialextent of the first diameter shank portion; inserting the smaller shankportion through the hole in the metal plate; and cold forming thesmaller diameter shank portion to expand it and fit it securely into themetal plate.
 5. The method according to claim 4, wherein the stud fixingconfiguration is an external thread.
 6. The method according to claim 4,wherein the exterior of the smaller diameter shank portion of the studhas a plurality of axial raised ribs.
 7. The method according to claim6, wherein the ribs of the stud extend substantially from the base ofthe groove but do not extend away from the head as far as the end of thesmaller diameter shank portion.
 8. The method according to claim 4,wherein the base of the groove has a plurality of substantially radialribs.